Spoilery context:

The Hisuian variants of the three Pokémon are noticeably different from what was shown. Brief descriptions follow in next tweet to keep this reply spoiler-free, but Bulbapedia has a more comprehensive description of each Hisuian Pokémon in its respective article.

Decidueye has red feathers instead of green, a different-looking head and crest, and black feet. Typhlosion looks high (and has a different color mane corresponding to its Ghost type, not shown). Samurott has black and red shells instead of yellow, and they look sharper.